This invention relates to detection and tracking systems and techniques and more particularly to an improved optical system and technique for detecting, locating and/or tracking various objects.
The technique of illuminating an object with electromagnetic radiation and receiving such radiations that are reflected from the object as a means of detecting and locating it is well known. One characteristic of radar systems is that the received signal is indicative primarily of the size of the object. The dependence of the received signal on the chemical composition of the object is very weak, and in most situations discrimination of objects based on chemical composition is not possible. Reflections from undesired objects are therefore often indistinguishable from those of desired objects. An example of this problem is ground clutter in land based microwave radar systems. There are applictions where use of a radar-like technique to identify a substance on the basis of its composition is both desirable and useful and a need exists for a system capable of deriving such information.